Flapper, adjustable ECU, strange screw?

[V8 Fettler]

I've picked up a spare ECU for a flapper (Lucas 4CU), it turns out it's adjustable, W to R must be weaken to rich (how does it do that? Modify the input from the coolant temp sensor?), but what is the other thing? A shielded screw to adjust a pot? Any suggestions please! Will need to open it up and have a look.

[adam quantrill]

Looks like it - the screw will be turning a multiturn pot inside.

I think they fiddle with the inputs a bit (plus there will be a piggy back board inside, most likely) to lengthen the injector pulses.

[V8 Fettler]

Thanks Adam

This pdf from HonestJohntoo...

http://www.vintagemodelairplane.com/pages/Download...

...suggests one pot for light throttle running and one for full throttle

[adam quantrill]

The thing is once you get to 100% duty cycle you can't increase the fuelling any more. So you have to go to bigger injectors or higher pressure.

They may be better used to _reduce_ the power (when using bigger injectors) which then gives you more to pour down the engine's throat when you floor it...

[Wedg1e]

adam quantrill said:

The thing is once you get to 100% duty cycle you can't increase the fuelling any more. So you have to go to bigger injectors or higher pressure.

They may be better used to _reduce_ the power (when using bigger injectors) which then gives you more to pour down the engine's throat when you floor it...

I went with slightly bigger injectors, lower fuel pressure and an inlet manifold with less porting work than NCK's original and got 256bhp. If I up the fuel pressure it drives like a dog until 4000rpm when it's like being thrown off a cliff